Recognizing the potential hazards of ionizing radiation to various bodily organs, medical practitioners have expressed considerable interest in carefully managing the amount of x-ray radiation that is delivered to patients for radiographic imaging. Aspects of prudent management for radiation exposure include limiting the overall amount of radiation exposure when planning and carrying out each individual examination as well as tracking exposure of the patient to x-ray radiation over time. The need for this type of management, while appropriate for patients of all ages, is particularly challenging and acute for the pediatric patient population, in which patient size varies over a broad range. Patient weight, for example, can vary over a range from about 1 kg to more than 100 kg in pediatric imaging.
Calculation of exposure received by a patient is complicated by a number of factors. Different energy levels are set up in the technique used for radiography, depending on the type of examination, along with different source-to-detector (SID) and source-to-patient distances. Dose and image quality often represent a tradeoff, calling for judgement by the practitioner in setting technique parameters. Different parts of the anatomy exhibit different response to x-ray radiation, due to variations in relative density and other characteristics, and may absorb different spectral portions of the radiation received. Some organs are more sensitive to radiation than others. Patient sex, weight, and thickness are also factors that can affect the actual amount of exposure received.
Conventional approaches to the problem of exposure calculation, prediction, and tracking fall short of what is needed. For calculating the amount of exposure received by a patient in a particular examination, for example, approximation of exposure typically uses look-up tables with statistically averaged values, based on numerous assumptions about the patient and about the imaging conditions that may not be accurate. For technique setup before acquiring the x-ray image, an index or exposure level may be automatically generated or recommended, but may be inaccurate, setting parameters to levels that do not properly account for patient physiology. The resulting lack of information, or poorly set parameters, can lead to increased and unnecessary x-ray exposure. This is a particular concern for children, the most sensitive segment of the population exposed to x-ray radiation.
Thus, it can be seen that there is a need for improved methods that more accurately determine and communicate x-ray dose information and recommendations.